CHICAGO — In a ruling that could revolutionize college sports, a federal agency said yesterday that football players at Northwestern who get scholarship money are effectively school employees and can vote on organizing what could become the first labor union for U.S. college athletes.

The decision by a regional director of the National Labor Relations Board answered the question at the heart of the debate over the unionization bid: Do football players who receive full scholarships to the Big Ten school qualify as employees under federal law and qualify to legally unionize?

Peter Sung Ohr, the NLRB regional director, said in a 24-page decision that the players “fall squarely” within the broad definition of employee.

The school said it will appeal to the NLRB in Washington. If Ohr’s decision is upheld, the case likely would make its way through appellate court and, perhaps, the Supreme Court.

A secret-ballot union vote amongst Northwestern players could proceed soon despite Northwestern’s appeal, according to Tim Waters, the political director for the United Steelworkers, which has footing the legal bills.

For now, the push is to unionize athletes at private schools, such as Northwestern University, because the federal labor agency does not have jurisdiction over public universities, such as Ohio State University. But yesterday’s decision opens the door for scholarship athletes at public universities to move more quickly to unionize because state labor boards, which govern public universities, usually follow labor-law interpretations issued by the NLRB.

The decision is “revolutionary for college sports,” said Robert McCormick, a professor emeritus at Michigan State University’s law school who focuses on sports and labor law.

McCormick said Ohr’s decision could influence state and federal agencies. For example, if players demand compensation for injuries sustained during training or a game, Ohr’s opinion could come into play in the question of whether the players are employees under workers’ compensation laws.

An employee is regarded by law as someone who, among other things, receives compensation for a service and is under the strict, direct control of managers. In the case of the Northwestern players, coaches are the managers and scholarships are a form of compensation, Ohr concluded.

The Evanston, Ill., university argued that college athletes, as students, do not fit in the same category as factory workers, truck drivers and other unionized workers. But supporters of the union bid argued that the university treats football as more important than academics for scholarship players.

Ohr agreed.

“The record makes clear that the employer’s scholarship players are identified and recruited in the first instance because of their football prowess and not because of their academic achievement in high school,” Ohr wrote. He also noted that “no examples were provided of scholarship players being permitted to miss entire practices and/or games to attend their studies.”

The ruling also described how the life of a player at Northwestern is far more regimented than that of a typical student, down to requirements about what they can eat and whether they can live off campus or purchase a car. At times, players put 50 or 60 hours a week into football, Ohr said.

Alan Cubbage, Northwestern’s vice president for university relations, said the school disagrees with the regional director’s opinion.

The next step would be for scholarship players to vote on whether to formally authorize the College Athletes Players Association, or CAPA, to represent them, according to the NLRB decision.

The specific goals of CAPA include guaranteeing coverage of sports-related medical expenses for current and former players, reducing head injuries and potentially letting players pursue paid sponsorships.

Critics argue that allowing college players to unionize could hurt college sports in numerous ways, including raising the prospect of strikes by players or lockouts by athletic departments.

“Imagine a university’s basketball players striking before a Sweet 16 game demanding shorter practices, bigger dorm rooms, better food and no classes before 11 a.m. This is an absurd decision that will destroy intercollegiate athletics as we know it,” U.S. Sen. Lamar Alexander, R-Tenn., said.

William Gould IV, a former chairman of the NLRB, said he is confident the NLRB will upheld Ohr’s decision.

“This is going to rattle the universe of universities,” Gould said.

The NCAA has been under increasing scrutiny over its amateurism rules and is fighting a class-action federal lawsuit by former players seeking a cut of the billions of dollars earned from live broadcasts, memorabilia sales and video games. Other lawsuits allege the NCAA failed to protect players from head injuries.

The NCAA said it disagrees with the notion that student-athletes are employees.

“We frequently hear from student-athletes, across all sports, that they participate to enhance their overall college experience and for the love of their sport, not to be paid,” the NCAA said in a statement.

Ohr’s ruling addresses a unique situation in American college sports, where the tradition of college competition has created a system that relies on players who are not paid. In other countries, elite youth athletes turn pro as teens, and college sports are small-time club affairs.

Outgoing Northwestern quarterback Kain Colter took a leading role in establishing CAPA. Colter said the top reason to unionize is to ensure injured players are taken care of.

“With the sacrifices we make athletically, medically and with our bodies, we need to be taken care of,” Colter told ESPN.

Attorneys for CAPA argued that college football is, for all practical purposes, a commercial enterprise that relies on players’ labor to generate billions of dollars in profits. The NLRB ruling noted that from 2003 to 2013 the Northwestern program generated $235 million in revenue.

During the NLRB’s five days of hearings in February, Wildcats coach Pat Fitzgerald took the stand for union opponents, and his testimony sometimes was at odds with Colter’s.

Colter told the hearing that players’ performance on the field was more important to Northwestern than their in-class performance, saying, “You fulfill the football requirement and, if you can, you fit in academics.” Asked why Northwestern gave him a scholarship of $75,000 a year, he responded: “To play football. To perform an athletic service.”

But Fitzgerald said he tells players academics come first, saying, “We want them to be the best they can be … to be a champion in life.”

Information from the Chicago Tribune, Bloomberg News, The New York Times and Reuters was included in this story.